Materials Literature
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Neutron diffraction and inelastic neutron scattering in zero field have been performed on mesoscopic magnetic ${\mathrm{Mn}}_{12}{\mathrm{O}}_{12}$ clusters, well known for their macroscopic quantum effects observed at low temperature. In addition to the static spin correlations of the cluster in its ground state, we…
Thin films of (Ba,Sr)TiO3 on Pt/SiO2/Si substrates were deposited using rf magnetron sputtering at various substrate temperatures and O2/(Ar+O2) mixing ratios (OMR). The crystallinity of the films improved significantly as the OMR increased. The dielectric constant increased with increasing OMR and reached a maximum v…
The synthesis and structural and magnetic properties of the pentanuclear complex [(Ni(bpm) 2 ) 3 (Fe(CN) 6 ) 2 ]·7H 2 O ( 1 ) are reported. Complex 1 crystallizes in the tetragonal space group P 4 3 2 1 2 (No. 96) with the following cell parameters at 23(1) °C: a = b = 12.888(2) Å, c = 42.927(2) Å, V = 7130(3) Å 3, an…
A new mode of polymerization of glycidyl acetate ( 1a ) to yield a poly(ortho ester), i.e., poly[(2-methyl-1,3-dioxolane-4,2-diyl)oxymethylene] ( 3a ), was explored. This new polymerization exclusively proceeded when a bulky Lewis acid, methylaluminium bis(2,6-di- tert -butyl-4-methylphenoxide) ( 2a ), was employed as…
Abstract On treatment of allyl-t-butyldiphenylsilane with t-BuOK and 18-Crown-6 in DMSO at room temperature, isomerization of the olefinic double bond and subsequent substitution of phenyl group with hydroxy group took place smoothly to afford alkenylsilanol derivatives in good yields.
An alternative system which could be an interesting candidate for electrochromic material is presented. The system is based on the deposition and stripping of a lead thin film on indium‐tin oxide‐coated glass (ITO).The electrodeposition and electrodissolution of lead was performed by cyclic voltammetry or potentiostat…
This study proposes a methodology for modeling the fatigue response of cross-ply ceramic matrix composites (CMCs). The micromechanics based analysis and failure criteria are formulated to model stress-strain hysteresis, strain ratchetting and S-N behavior specific to room-temperature cyclic loading environments. The d…
When a hot solid particle is submerged into an ambient fluid near a free liquid-gas interface, a non-uniform temperature field around the particle produces surface tension gradients at the interface and generates thermocapillary flow in the surrounding fluid. This flow sets the particle itself in motion towards or awa…
L'oxydation sous air a haute temperature des alliages base titane α de type IMI 834 et TIMETAL 1100 conduit a la formation de couches oxydees non protectrices. Par ailleurs, la solubilisation d'oxygene dans l'alliage fragilise ce dernier en diminuant sa ductilite. Une amelioration de la tenue a l'oxydation et une prev…
This paper is the first part of a series reporting on the recent development of a yarn modification process to produce torque-balanced singles spun yarns. Taking advantage of the core-sheath structure of unconventionally spun yarns, we have developed a yarn modification process and applied it to singles yarns spun by…
The kinetics of thermal decomposition of epoxy resin are investigated under various heating rates (2, 5, 10, and 20 K/min) and oxygen concentrations (5, 10, and 20%) in the nitrogen-oxygen atmosphere by means of thermogravimetric measurements. Results show that, unlike only one stage of reaction in the inert atmospher…
A new computer model is developed to predict the tensile behavior of nonwoven fabrics from the stress-strain behavior of their constituent fibers and distributions of fiber orientation angles. The finite element method is used to calculate the numerical solution of stress and strain distribution in different regions o…
Two new puriniums, heteromines D (4) and E (5), and three new pyrimidines, heteromines F (6), G (7), and H (8), were isolated from the aerial parts of Heterostemma brownii Hay. Their structures were determined as 7,9-dimethyl-2-(N,N-dimethylamino)guaninium chloride, 7,9-dimethyl-2-(N-methylamino)guaninium chloride, 6-…
Abstract A new class of biodegradable copolyesters was prepared by polycondensation of sebacoyl chloride with mixtures of silylated isosorbide and silylated O , O ′‐bis(2‐hydroxyethyl)hydroquinone in bulk. A class of poly(ester‐anhydride)s was synthesized from sebacoyl chloride and mixtures of silylated O , O ′‐bis(2‐…
Raman and infrared spectra of a bisphenol-A-containing azoaromatic polyether, a bisphenol-A-containing azoxyaromatic polyether and a bisphenol-A-containing 2-hydroxyazoaromatic polyether were analyzed. Vibrational spectra were also collected for the corresponding model compounds 4,4′-(4-tert-butylphenoxy)azobenzene, 4…
Strengths and Weibull moduli for alumina/yttrium aluminum garnet eutectic (AYE) filaments and for Si‐C‐O (Nicalon TM ) filaments were calculated using measured and average filament diameters. The strengths agreed closely. Thus an average filament diameter could be used instead of the measured filament diameter in calc…
Abstract Self‐doped polyaniline modified electrodes were successfully fabricated by copolymerization of aniline and m ‐aminobenzoic acid in 0.5 mol L −1 sulfuric acid. The electrochemical characteristics of this resulting polymer were investigated. The polymer displayed electrochemical activity with the formal potenti…
A novel polymeric organosilicon gel with the composition [MeSi(NCN)1.5]n synthesized by the reaction of MeSiCl3 with Me3Si–N=C=N–SiMe3 is reported. The reaction is performed without any solvent and with catalytic amounts of pyridine and provides highly cross-linked poly(methylsilsesquicarbodi-imide) in the form of a s…
In the TiO 2 ‐SiO 2 system, anatase solid solutions (ss) containing up to similar/congruent ∼15 mol% SiO 2 are formed in the as‐prepared state by the hydrazine method. The lattice parameters a and c decrease linearly from 0.3785 to 0.3776 nm and from 0.9514 to 0.9494 nm, respectively, with increased SiO 2 content. At…
We report on an experimental and numerical study of tilted dendrites observed in thin-film directional solidification of a ${\mathrm{CBr}}_{4}{--8\mathrm{}\mathrm{mol}\mathrm{}%\mathrm{}\mathrm{C}}_{2}{\mathrm{Cl}}_{6}$ alloy for an arbitrary orientation of the crystal with respect to the plane of the sample and the p…